I have a set of 2000 Si rims. I was just wondering what is the widest set of tires i could put on them?

 

How wide are the whheels? 15, 16, 17, or 18's. More than likely 15's. 195 or a 205. Anything wider and you'll be "pinching" the tire on the wheel.

 

It also depends on the suspension setup, the tire diameter,and the offset of the rims. Saying that, I would think almost any tire wider than a 205 wouldrub on a pre-'06 Civic, either on the inner fender or suspensionfrom being too far in, or the outer fender from sticking too far out.